electronhttp://home.web.cern.ch/taxonomy/term/45/all
enElectrons at the LHC: a new beginninghttp://home.web.cern.ch/scientists/updates/2014/07/electrons-lhc-new-beginning
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<a href="/authors/christine-sutton" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Christine Sutton</a></p>
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<p>The only particle collider so far to have exploited electron-proton collisions at high energies was HERA at <a href="http://www.desy.de/">DESY</a>, where the H1 and ZEUS experiments provided some surprising results much of the base for physics at the LHC. Building on the conceptual design study for an electron-beam upgrade to the LHC — the <a href="/about/accelerators/large-electron-positron-collider">Large Hadron Electron Collider</a> (LHeC) — CERN’s management recently set up an International Advisory Committee to investigate these possibilities further. One of the committee’s first major activities was to organize a workshop on the LHeC concept, its physics and accelerator and detector development.</p>
<p><strong>Read more:</strong> "<a href="http://cerncourier.com/cws/article/cern/57304">Electrons at the LHC: A new beginning</a>" <em>– CERN Courier </em></p>
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Wed, 02 Jul 2014 07:37:46 +0000coluanai44293 at http://home.web.cern.chThe Large Electron-Positron Colliderhttp://home.web.cern.ch/about/accelerators/large-electron-positron-collider
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<img typeof="foaf:Image" src="http://home.web.cern.ch/sites/home.web.cern.ch/files/styles/medium/public/image/accelerator/2013/01/lep.jpg?itok=CbITGHoh" width="800" height="1067" alt="" /> </div>
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<p>With its 27-kilometre circumference, the Large Electron-Positron (LEP) collider was – and still is – the largest electron-positron accelerator ever built. The excavation of the LEP tunnel was Europe’s largest civil-engineering project prior to the Channel Tunnel. Three tunnel-boring machines started excavating the tunnel in February 1985 and the ring was completed three years later.</p>
<p>In its first phase of operation, LEP consisted of 5176 magnets and 128 accelerating cavities. CERN’s <a href="/about/accelerators">accelerator complex</a> provided the particles and four enormous detectors, <a href="/about/experiments/aleph">ALEPH</a>, <a href="/about/experiments/delphi">DELPHI</a>, <a href="/about/experiments/l3">L3</a> and <a href="/about/experiments/opal">OPAL</a>, observed the collisions.</p>
<p>LEP was commissioned in July 1989 and the first beam circulated in the collider on <a href="http://timeline.web.cern.ch/timelines/The-Large-Electron-Positron-Collider/overlay#1989-07-13 23:15:00">14 July</a>. The collider's initial energy was chosen to be around 91 GeV, so that Z bosons could be produced. The Z boson and its charged partner the W boson, both discovered at CERN in 1983, are responsible for the weak force, which drives the Sun, for example. Observing the creation and decay of the short-lived Z boson was a critical test of the Standard Model. In the seven years that LEP operated at around 100 GeV it produced around 17 million Z particles.</p>
<p>In 1995 LEP was upgraded for a second operation phase, with as many as 288 superconducting accelerating cavities added to double the energy so that the collisions could produce pairs of W bosons. The collider's energy eventually topped 209 GeV in 2000.</p>
<p>During 11 years of research, LEP's experiments provided a detailed study of the electroweak interaction. Measurements performed at LEP also proved that there are three – and only three – generations of particles of matter. LEP was closed down on 2 November 2000 to make way for the construction of the <a href="/about/accelerators/large-hadron-collider">Large Hadron Collider</a> in the same tunnel.</p>
<p><iframe class="timeline" scrolling="no" src="//timeline.web.cern.ch/timelines/The-Large-Electron-Positron-Collider/export"></iframe></p>
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Wed, 25 Jul 2012 07:48:45 +0000coluanai997 at http://home.web.cern.chThe Compact Linear Colliderhttp://home.web.cern.ch/about/accelerators/compact-linear-collider
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<img typeof="foaf:Image" src="http://home.web.cern.ch/sites/home.web.cern.ch/files/styles/medium/public/image/accelerator/2013/01/clic.jpg?itok=BrsANB20" width="800" height="465" alt="" /> </div>
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<p>Physicists and engineers at CERN are pursuing advanced accelerator research and development for a machine to exploit the <a href="large-hadron-collider">Large Hadron Collider</a>’s discoveries at the high-energy frontier. The <a href="http://clic-study.org/">Compact Linear Collider (CLIC) study</a> is an international collaboration working on a concept for a machine to collide electrons and positrons (antielectrons) head-on at energies up to several teraelectronvolts (TeV). This energy range is similar to the LHC’s, but using electrons and their antiparticles rather than protons, physicists will gain a different perspective on the underlying physics.</p>
<p>The aim is to use <a href="/about/engineering/radiofrequency-cavities">radiofrequency</a> (RF) structures and a two-beam concept to produce accelerating fields as high as 100 MV per metre to reach a nominal total energy of 3 TeV, keeping the size and cost of the project within reach. The CLIC test facility, CTF3, provides the electron beam for the studies.</p>
<p>In the two-beam acceleration concept, the high RF power needed to accelerate the main beam is extracted from a second high-intensity electron beam – the “drive beam” – that runs parallel to the main beam. This drive beam is decelerated in special power extraction structures and the generated RF power is used to accelerate the main beam.</p>
<p>In a related project, the <a href="/about/clicdp">CLIC detector and physics collaboration</a> is developing a detector to record collisions at the future high-energy Compact Linear Collider.</p>
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Mon, 23 Jan 2012 14:20:31 +0000coluanai47 at http://home.web.cern.chSubatomic particleshttp://home.web.cern.ch/about/physics/subatomic-particles
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CERN scientists are probing the fundamental structure of the universe to find out what the elementary particles are and how they interact </p>
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<p>Scientists at CERN are trying to find out what the smallest building blocks of matter are.</p>
<p>All matter except dark matter is made of molecules, which are themselves made of atoms. Inside the atoms, there are electrons spinning around the nucleus. The nucleus itself is generally made of protons and neutrons but even these are composite objects. Inside the protons and neutrons, we find the quarks, but these appear to be indivisible, just like the electrons.</p>
<p>Quarks and electrons are some of the elementary particles we study at CERN and in other laboratories. But physicists have found more of these elementary particles in various experiments, so many in fact that researchers needed to organize them, just like Mendeleev did with his periodic table.</p>
<p>This is summarized in a concise theoretical model called the <a href="standard-model">Standard Model</a>. Today, we have a very good idea of what matter is made of, how it all holds together and how these particles interact with each other.</p>
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Fri, 20 Jan 2012 14:10:25 +0000coluanai33 at http://home.web.cern.ch